Window



M. D. McoRMlcK v 2,207,065

WINDOW Filed Oct. 19, 1937 2 Sheets-Sheet. l

if' Z .30 F29 9 33 ff- "Jg E 30 .29.9v l y 3f-H j@ 16 25 faz/@2522917 July 9, 1940. M. D. MccoRMxcK WINDOW Filed oct. 19, 1957 2 Sheets-Sheet 2 Patented July 9, 1940 Maurice D'. McCormick, Chicago, Ill., assignor'of one-half to Stanley Werdell, Chicago, Ill.

Application october 19, 1937, serial No. 169,839

' 22 claims. (01. .2o-48) My invention relates to windows,and ismore particularly concerned with mechanism forsealing rotary-mountedwindow panes.

In its more specific phases my invention conof Fig. 2;

Fig. 4 is a typical vertical transverse section through the lower rails of the main and subsashes taken on the line 4-4 of Fig. l but on an enlarged scale;

Fig. 5 is a section similar to Fig. 4 but taken along the axis of rotation; Y

Fig. 6 is a vertical section taken on a medial plane of the sash showing the upper right hand the lower edge in Fig. 4-of each rail of the subsash is formed with a V-shaped groove 2 l, which receives the complemental V-,edge 22 of the sealing strip I9.

AThe fitting of the sealing strips I9 intov the 5 templates a double hung or easement sashin corner thereof with the sealing strip in closed 5 which thepane itself is mounted in `a subsash position; rotataby mounted in the main sash, whereby the Fig. 7 is a section similar to Fig. 6 but showing pane together with its subsash may be turned the sealing strips in their released position; and around to facilitate washing both sides, or'in Fig. 8 is a view similar to Fig. 7 but on a re- 10 some instances-for providing ventilation also. duced scale showing a modied form of operating 10 As applied to such a construction, my invention mechanism for the releasable sealing strips. is especially concerned with means forlocking I have here illustrated my invention as inthe rotatable subsash in its closed position and corporated in the upper and lower Sashes of a for sealing it against the weather. Preferably, double hung window, althoughI contemplate that the subsash will be pivoted to the main sash along correspondingy embodiments maybe incorporated 15 a medial vertical line, although I contemplate in easement sash. l that the subsash may be mounted to pivot about The sash I@ is slidably mounted in the window its edge to the main sash afterthe fashion of frame f il in the usual manner. The sash I0 a Casement sash. comprises a main or outer sash I2 anda sub- 3 I contemplate also that the member' corre- .sash or inner sashl I3 mounted in the planeof 20 spending to the subsash may itself constitute the the main sash and surrounded thereby. The sole movable sashfor the pane and be mounted subsash vis so mounted in the main sash that in a fixed frame, rather than in a movablek main it pivots about a medial vertical ams along the sash, this being especially suited for the so-called line 5,-5 of Fig. 1, ythis mounting being eiected xe'd windows of air-conditioned homes and by upper and lower pivot pins shown in Fig. 5, 25 buildings, as will subsequently be explained. The. glass A further objectof my invention is a positionpane I 4 is carried directly by the subsash, aling and sealing device for the subsash cooperatthough the glazing may be subdivided into smaller ing with all four edges thereof but releasable by panes by the usual muntins, if desired.

asingle manual operating member when the pane The body of the main sash I 2 is formed by 30 is to be rotated for cleaning or ventilation. A four rails l5 constituting itsr respective sides, top still further object is a set of releasable sealing and bottom, the rails being mitered at thecorstrips for the several edges of the subsash which, ners. yPreferably the rails I5 are built up from whileitself light and small in size, is so mounted sheet metal and for convenience are formed in that it effects a rm weather seal throughout the two halves-an interior half E-i and an ex- 35 margins of the subsash. terior half IE-e. The tworail halves I5-e and Still another'object is a releasable locking and Y ,I5-i Yare arranged t0 Contact MODS their inner sealing mechanism for the subsash which can margins near the bottom (in the instance 0f the be released only by the use of a key by authorized bottom rail as shown in Fig. 4), where they are y4() persons, such as window cleaners or janitors, but held together by screws I. Thereabove the inner 40 which discourages rotationv of the subsash by faces of the rail halves are spaced apart to form occupants or tenants instead of raising or opena deep slot I7, and near the top of the rail ing the main sash for the purpose of ventilation. halves the slot is enlarged to a wide slot portion The foregoing together with'further objects, |8- yCOIleSlDOHdng SlOJS in the Side and 130D features and advantages of Amy invention are set Tails Similarly Open toward the subsash i3. 45 forth in the following description of specific em- A Sealing Strip l@ iSy dSlOOSed n each slot Il and bodiments of my invention illustrated in the acis normally insealmg Contact With the adjacent Companying drawing-S wherein; rail of thersubsash I3. The ends of the sealing Fig. l is an inside elevation of the-lower sash Strlp 'are normally 1n Contact at the cornersofof a double hung window showing the rotary gpalgb Vlrtue of the bemg Entered as 50 pane in closed position; l i l Each rail of the subsash i3 1s preferably of Flgmas da'tlgulr glsiolfmwmg the rotary extruded metal stock. Each rail is rabbetted for palle h e D P p the reception of the glass Ill, which is held in Fig. 3 1s a plan section taken on the line 3`3 position by a glazing Strip M The Outer edge 55 grooves 2| of the subsash serve the two-fold purpose of locking the subsash against rotation and effecting a weather seal between the subsash and the main sash.

The pivotal mounting of the subsash in the main sash is effected by a pair of pivot pins or trunnions 23 and 23 (Fig. 2). The lower pivot pin 23 is shown in Fig. 5. Its upper end is received in a counterbore 24 in the lower rail of the subsash I3 at the medial point thereof. The pivot pin passes through a bore 25 in the lower sealing strip I9. The lower end of the pivot pin is received in the socket 28% of a socket block 21 interposed between the inner faces of thesash halves I5-e and IE-z which denne the walls oi` the slot I1. The block 21 is welded or otherwise xed to one of the slot faces. The setting of the lower end of the pin 23 in the socket 26 aords a thrust bearing to carry the weight of the subsash I3 and the pin 23 serves to keep the subsash I3 in a vertically xed position in reference to the main sash.

Y A similar pivot pin 23 (Figs. 2 and 6) is ernployed in the respective upper rails of the main sash and subsash in axial alignment with the lower pivot pin 23, and this upper pivot pin is similarly arranged and performs the same function except that, obviously, it does not necessarily bear the weight of the subsash.

I shall now describe the mechanism by which the four sealing strips are held in their normal closed position against the outer edge faces of the subsash, that is, held in the positions indicated in Figs. 4 and 5.

A controlling bar 28, preferably of channel shaped cross section, is disposed adjacent the bottom of each slot I1, as shown in Figs. 4 and 6. There are thus four control bars 28. Each control bar is mounted for limited longitudinal reciprocation by virtue of a plurality of cross pins 2S extending through the flanges of the channel shaped control bar 28 with their ends extending into slots 30 in those portions` of the main sash halves I5-e and I5-z which denne the slot I1.

The adjacent ends of the four control bars 28 are interconnected by short lengths of -cable 3I which pass over pulleys 32 journaled in the corners of the slots I1 and within the corners of the outer sash, as best shown in Fig. 6. The four bars 28 and their interconnecting cable lengths 3l thus form a composite endless chain, whereby when one of the bars 28 is shifted longitudinally, the other three bars are simultaneously shifted and to the same extent.

Each sealing strip I9 is operatively connected with the adjacent operating bar 28 by a set of links 33. The outer end of each link 33 is pivoted to the operating bar 28 by one of the pins 29, previously described. 'I'he inner end of eac-h link is pivotally connected to the sealing strip I9 by a cross pin 34. The ends of each cross pin 34 also pass through transverse slots 35 in the walls of the main sash rail halves which define the slot I1.

The slots 3l] for the pins 23 are arranged longitudinally (in reference to the sash rail, sealing strip and operating bar 28), Whereas the slots 35 for the pins 34 are arranged transversely. As a result, if the sealing strips are in the closed position of Fig. 6 and one of the bars 28 is shifted longitudinally, the outer end of each link 33 will be constrained to follow a longitudinal path in its slot 30, whereas the inner end of each link 33 will be constrained to follow a transverse outward path in its slot 35. Consequently the longitudinal shifting of the control bars is translated, by the connecting cables 3| are arranged to form an endless unit, operating movement may be applied at any point. One expedient I have illustrated -consists of a nger lug 36 attached to one of the control bars 28, as shown in Fig. 6. This lug extends through a slot in the face of the sash where the end of the lug is exposed to the interior of the building, as shown in Figs. l and 2. By pulling the lug 36 down the immediate bar 28 and consequently all the other bars 28 are shifted, which in turn transversely shifts the sealing strips I9 to their outer or released position. The lug 38 may be releasably held in either its closed or open position by a spring clip 31, as indicated in Fig, 6.

The upper and lower ends, respectively, of the clip form spring nger detents. When the bar 28 is in its upper position the upper spring finger engages the lower side of the lug 36. When the bar 28 is in its lower position, the lower spring nger engages the upper side of the lug. The spring of the lingers of the clip 31 yields to permit the lug being snapped from one position to the other.

Another expedient for effecting the shifting is to form the trunnions of one of the pulleys 32 with a square bore 38, as shown in Fig. 6.

A square key (not shown) may then be inserted through a suitable opening in the exposed face of the main sash and into the square bore 38 whereby the pulley 32 may be turned. The groove of the pulley should, of course, be conformed to alford more positive traction with the cable, or a chain and sprocket may be substituted for the cable and pulley. This key expedient has the advantage that the keys may be kept in the possession of the window washers of public buildings and factories, so that ther pane will be rotated only for cleaning and the occupants or tenants will be forced to raise the sash for ventilation. When the rotatable sash constitutes a subsash within a main sash, it will be too light to stand the strains and abuse to which it would be subjected if it were frequently left open for ventilation.

In Fig. 8 I have illustrated an alternative method of interconnecting the four control bars 28 for simultaneous shifting. This is eiected by means of a bell crank 39 in lieu of the cable 3| and pulley 32. The pivotal interconnection of the ends of the bell crank to the ends of the bars 28 will include a slightly transversely elongated slot, whereby the shifting of each control bar 28 may be maintained strictly rectilinear as guided by the slots 30.

The transverse outward shift applied to each sealing strip I9 by movement of the control bars l28, as previously described, withdraws the sealing strip into its slot I1 far enough to clear the outer edge of the adjacent rail of the subsash I 3. The subsash is then free to rotate about its aligned pivot pins or trunnions 23 and 23'. This enables the window washer to clean both sides of the pane from the inside of the building.

Because the movement imparted to the sealing strip is strictly a transverse movement that is, a movement in a direction transverse to the length of the strip, and the transversely disposed pivot pins 23 and 23' are Slidable in reference to their transverse bores 25 in the upper and lower sealing strips, the presence of the pivot pins does not interfere with the transverse shifting of the sealing Strips.

Preferablyalthough not 'necessarily-a weather stripping 40 is interposed between each sealing strip I9 and its slot I1. It is for this purpose that the mouth over each slot I'I is enlarged as indicated at I8. The weather stripping 46 may be of metal or other standard weather strip-ping construction which will permit the transverse shifting of the sealing strip I. Preferably, however, the weather stripping 40 is of composite fabric and rubber packed into the slot I8 to maintain a weather seal between the slot and the sealing strip I9 without offering too much friction against shifting of the strip. On the exterior side-that is the side exposed to the weather-the weather stripping 40 is formed obliquely at its upper edge along the bottom rail of the main sash, as indicated in Fig. 4, and the chamfered upper edge of the lower rail half I5-e is lowered into oblique alignment therewith. The purpose is to direct water downwardly and away from the sealing strip I9 where it might freeze and olfer excessive resistance to shifting. For the same purpose, I prefer to extend the lower exterior edge of the lower rail of the-'subsash I3 into an overhanging drip edge IS'. Water running down the pane and across the bottom rail of the subsash-is thus carried across and beyond the line of contact between the exterior weather stripping 40 and the sealing strip I9,

As a further weather seal, I prefer to provide a resilient rubber strip 4I disposed within a square slot at the base of the V-shaped groove 2l in the edge face of the subsash I3. The rubber strip GI is normally square or rectangular in cross section, but is deformed by the apex of the sealing strips I9, as shown in Fig. 4, which presents a particularly tight weather seal supplementing the contact of the mating V-shaped surfaces 2I and 22 on each side thereof.

'Ihe sealing strips I9` may be relatively light, even much lighter than here shown. Even though they may, therefore, have considerable flexibility, this flexibility does not interfere with the continuity and security of the seal they eiect with thersubsash. That isbecause inward pressure is applied to the sealing strip at relatively close intervals, depending upon how many links 33 are employed. The control bars are subject .only to longitudinal strain, and not `to transverse strain; therefore, they may be relatively light also.

I contemplate that where so-called xed' windows are to be employed, such as in air-condi'-l tioned buildings and homes, the member corresponding to what I have here described asy the main sash, may be a fixed sash, or in fact maybe a part of the window frame. The rotatable subsash I3 may thus constitutevthe only movable sash, and be moved only for window cleaning.

While I have described and illustrated these specific embodimentsV of my invention, I' contemplate that many changes andi modifications may be made thereover without departing from the scope or spirit of my invention.

I claim:

l. A window comprising aninner sash, a`sash like member framing the inner sash, meansy for pivotally` mounting the innersashfor 'rotation in the` sash-likeg-member, ,ai sealing stripumountedl in the sash-like member along each side of the inner sash and having a weather sealing engagement with the innersash, a control bar mounted along each side of the sash-like member for longitudinal reciprocation, and mechanism interconnecting each control bar with its respective sealing strip for `shifting'the sealing strip, the several control bars being interconnected for common longitudinal actuation to shift the sealing strips.

2. A window comprising an inner sash, a sashlike member framing the inner sash, means for pivotally mounting the inner sash for rotation in the sash-like member, a sealing strip mounted 'in the sash-like member along'each side of the inner sash and having weather sealing engagement with the inner sash, a control bar extending along each side of the sash-like member and mounted therein for longitudinal reciprocation, means interconnecting the control bars for joint reciprocation, and mechanism interconnecting each control bar with its associated sealing strip for translating the longitudinal reciprocation of the control bars into transverse shifting of the sealing strips.

3. A window comprising an inner sash, a sashlike member framing the inner sash, means for pivotally mounting the inner sash for rotation in the sash-like member, a sealing strip mounted in the sash-like member along each side of the inner sash and having weather sealing engagement` with the inner sash, a control bar extending along each side of the sash-like member and mounted therein for longitudinal reciprocation, means interconnecting the control bars for joint reciprocation, and mechanism interconnecting each control bar with its associated sealing strip for translating the longitudinal reciprocation of the control bars into transverse shifting 'of the sealing strips, said mechanism including a plurality of links connecting each control bar toits f associated sealing strip.

4. A window comprising an inner sash, a sashlike member framing the inner sash, means for pivotally mounting the inner sash for rotation in the sash-like member, a sealing strip mounted in the sash-like member along each side of the inner sash and having weather sealing engagement with the inner sash, a control bar extending along each side of the sash-like member and mounted therein for longitudinal reciprocation, means interconnecting the control bars for joint reciprocation, andA mechanism interconnecting each control bar with its associated sealing strip for translating the longitudinal reciprocation of the control bars into transverse shifting of the sealing strips, said mechanism including a plurality` of links connecting each control bar to its associated sealing strip, and guide slots carried bythe vsash-like member confining the inner ends of the links to transverse movement and the outerv ends of the links to longitudinal movement.y

5. Ar window comprising an inner sash, an outer sash framing the inner sash, opposed pivot pins extending between the inner sash and outer sash for pivotally mounting the inner sash for rota- I' tion in the outer sash, an inwardly opening slot ineach rail of the outer sash facing the respective rails of the inner sash, a sealing strip mounted in each slot, the juxtaposed faces of each sealing strip and its associated innerv sash rail vbeing formed with complementary sealing surfaces, acontrol bar disposed in each slot outwardly of the sealing strip, means for mounting the control bars for longitudinal-reciprocation,.,meansfor interconnecting the control bars to shift longitudinally together, mounting means for the sealing strips coniining them to transverse movement, and a plurality of spaced links pivotally connected at their inner ends to the sealing strips and at their outer ends to the control bars whereby longitudinal reciprocation of the control bars is translated into transverse shifting of the sealing strips, and a common manually operated member for simultaneously shifting the control bars longitudinally to shift the sealing strips into and out of sealing engagement with the inner sash.

6. A window comprising an inner sash, a sashlike member framing the inner sash, means for pivotally mounting the inner sash for rotation in the sash-like member, a sealing strip mounted in the sash-like member along each side of the inner sash and having weather sealing engagement with the inner sash, a control bar extending along each side of the sash-like member and mounted therein for longitudinal reciprocation, means interconnecting the control bars for joint reciprocation, and mechanism interconnecting each control bar with its associated sealing strip for translating the longitudinal reciprocation of the control bars into transverse sluiting of the sealing strips, said control bar interconnecting means comprising pulleys within the corners of the sash-like member and lengths of cable connecting adjacent ends of the control bars and passing over the respective pulleys.

7. A window comprising an inner sash, a sashlike member framing the inner sash, means for pivotally mounting the inner sash for rotation in the sash-like member, a sealing strip mounted in the sash-like member along each side of the inner sash and having Weather sealing engagement wtih the inner sash, a control bar extending along each side of the sash-like member and mounted therein for longitudinal reciprocation, means interconnecting the control bars for joint reciprocation, and mechanism interconnecting each control bar with its associated sealing strip for translating the longitudinal reciprocation of the control bars into transverse shifting of the sealing strips, said control bar interconnecting means comprising a bell crank within each corner of the sash-like member having its arms connected respectively to the adjacent ends of the associated control bars.

8. A window comprising an inner sash, a sashlike member framing the inner sash, means for pivotally mounting the inner sash for rotation in the sash-like member, a sealing strip mounted in the sash-like member ralong each side of the inner sash and having weather sealing engagement with the inner sash, a control bar extending along each side of the sash-like member and mounted therein for longitudinal reciprocation, means interconnecting the control bars for joint reciprocation, and mechanism interconnecting each control bar with its associated sealing strip for translating the longitudinal reciprocation of the control bars into transverse shifting of the sealing strips, and a iinger piece connected to one of the control bars and exposed for manual manipulation exterioriy of the sash-like member for simultaneously operating all of the control bars to shift all of the sealing strips.

9. A window comprising an inner sash, a sashlike member framing the inner sash, means for pivotally mounting the inner sash for rotation in the sash-like member, a sealing strip mounted in the sash-like member along each side of the inner sash and havingA weather4 sealing engagement with the inner sash,v a control bar extendingalong each side of the sash-like member and mounted ther-ein for longitudinal reciprocation, means interconnecting the control bars for joint reciprocation, and mechanisml interconnecting `each control bar with its associated sealing strip for translating the longitudinal reciprocation of the control bars into transverse shifting of the sealing strips, a nger piece connected to one of the control bars and exposed for manual manipulation exteriorly of the sash-like member for simultaneously operating all of the control bars to shift all of the sealing strips, and a spring clip 'for yieldably holding the nnger piece in its closed and in its opened positions.

10. A window comprising an inner sash, a sashlike member framing the inner sash, means for .pivotally mounting the inner sash for rotation in the sash-like member, an inwardly opening slot in each rail'of the sash-like member, a sealing strip disposed in each slot and transversely shiftable therein, the outer face of each rail of the inner sash having a V-groove extending therealong,vthe inner face of each sealing strip having a longitudinally extending V-edge for sealing cooperation therewith, a longitudinally extending slot formed in the apex of the V-groove .of each rail of the inner sash, and a strip of resilient sealing material disposed therein, the parts being so constructed and arranged that when the sealing strips are in their inner or closed positions the apex of the V-edge of each sealing strip seals against said sealing material, and the oblique sides laterally thereof seal against the surfaces of the V-groove of the inner sash rail.

1l. A window comprising an inner sash, a sashlike member framing the inner sash, means for pivotally mounting the inner sash for rotation in the sash-like member, a sealing strip mounted in the sash-like member along each side of the inner sash and having Weather sealing engagement with the inner sash, a control bar extending along each side of the sash-like member and mounted therein for longitudinal reciprocation, means interconnecting the control bars for joint reciprocation, and mechanism interconnecting each control bar with its associated sealing strip fortranslating the longitudinal reciprocation of the control bars into transverse shifting of the sealing strip, said mechanism including a plurality of parallel spaced links, the outer end of each link being pivotally connected to the control bar and the inner end of each link being pivotally connected to the sealing strip, the construction and arrangement being such that the links occupy a transverse position in reference to the afssociated bar and strip when the sealing strips are in their closed or sealing position, but occupy an oblique position when the sealing strips are in their outer positions.

12. A window comprising an inner sash, a sashlike member framing the inner sash, means for pivotally mounting the inner sash for rotation in the sash-like member, an inwardly facing slot in each rail of the sash-like member, a sealing strip mounted in each slot along each side of the inner sash and having Weather sealing engagement therewith, a control bar in each slot outwardly of the sealing strip, and mounted in the slot for longitudinal reciprocation, means interoonnecting the control bars for joint reciprocation, and mechanism interconnecting each control bar with its associated sealing strip for translating the longitudinal reciprooation of the controlvbarsinto transverse shifting of the sealing strips, said mechanism including a plurality of spaced parallel links, an outer pivot pin connecting the outer end of each link to the associated control bar, an inner pivot pin connecting to transverse movement, the construction and arrangement of the mechanism being such that when the sealing strips are in their inner or sealing position the links are disposed transversely to hold the sealing strips in sealing vposition under endwise thrust of the links.

13. A window comprising an inner sash, an

with the outer edge of each rail of the inner sash,

a strip of lweather sealing material in the mouth of each slot and interposed between the wall of the slot and the side of the associated sealing strip for sealing the movable strip to the sash-like member, and means for transversely shifting the sealing members into and out of sealing engagement with the inner sash.

14. A window comprising an inner sash, an outer sash-like member framing the inner sash, means for pivotally mounting the inner sash for rotation in the sash-like member, an inwardly opening slot in each rail of the sash-like member, a sealing strip mounted for transverse movement in each slot, the inner edge of each sealing strip being conformed for weather sealing engagement with the outer edge of each rail of the inner sash, a strip of weather sealing material in the mouth of each slot and interposed between the wall of the slot and the side of the associated sealing strip for sealing the movable strip to the sash-like member, and means for transversely shifting the sealing members into and out of sealing engagement with the inner sash, the lower edge of the lower rail of the'inner sash, along its weather exposed side, having a drip lip overhanging the line of contact between the weather sealing material and the sealing strip to divert water therefrom.

15. A window comprising an inner sash, an outer sash-like member framing the inner sash, a slot formed in each rail of the sash-like member and facing the outer edge of the adjacent rail of the inner sash, a sealing strip shiftably mounted in each slot for sealing engagement with the outer edge of the adjacent rail of the inner sash, mechanism operating upon the sealing strips independently of substantial lateral thrust thereon in a direction perpendicular to the plane of the Y outer sash-like member, for shifting the sealing strips transversely of themselves, but parallel with the plane of the outer sash-like member, and without substantial longitudinal movement, into and out of sealing engagement with the inner sash, and a pair of aligned pivot pins disposed in opposed slots for journaling the inner sash for rotation within the outer sash-like member, each pivot pin passing through a hole in its adjacent sealing strip whereby the associated sealing strips may be transversely shifted independently of the pivot pins.

16. A window comprising an inner sash, an outer sash framing the inner sash, means for pivotally journaling the inner sash for rotation within the outer sash, each rail of the outersash comprising an interior (indoor) half and a generally similar exterior v(outdoor) half, means for holding the halves assembled and providing an inwardly opening slot between the halves in a central plane of the outer sash, a sealing strip mounted in eachy slot for shifting, transversely of itself, and relative to the outer sash, into and out of sealing engagement with the inner sash, and mechanism substantially concealed within the slots for shifting the strips into and out of ally mounted therein about. a medial axis, window glass rigidly carried by the inner sash, a set of sealing strips disposed along the respective sides of the sash and intermediate the inner and outer sash for sealing the inner sash to the outer sash, the sealing strips, when in their sealing position, sealing throughout the margin of the inner sash including its corners and the respective strips abutting at the corners, and mechanism including a common manually engageable member for shifting the strips transversely. of themselves outwardly from the inner sash to release their seals with the inner sash.

18. A window comprising a main sash, a subsash mounted therewithin to pivot about an axis closing the field of the sub-sash, a set of four sealing strips operatively disposed between the main sash and sub-sash along the respective sides of the the main sash--relative to the main sash, to the v sub-sash and to the other strips, into and out of sealing engagement with the sub-sash, the strips when in sealing position intersealing the main sash and sub-sash continuously about the margins off the sub-sash, including its corners.

19. A window according to claim 18 wherein the operating means is mounted interiorly of the rails of one of the sashes and substantially concealed thereby.

20. A window according to claim 18 wherein the operating means and the strips are mounted in the rails of the main sash and theoperating means is substantially concealed thereby.

21. A window according to claim 18 wherein the sealing strips are mounted in the main sash and the ends of the strips are mitered toform abutting miter joints when in sealing position.

22. A window according toI claim 18 wherein the sealing strips and the operating means are mounted in the main sash and the ends of the strips are mitered for abutment when the strips are in sealing position, and wherein the operating means includes a bell crank at each corner with its fixed pivot on the sash substantially in the line of miter with an arm extending on each side f MAURICE D. MCCORMICK. 

